1. Field of the Invention
The present invention is directed to Ethernet communication systems and, more particularly, to Ethernet physical layer devices.
2. Related Art
Ethernet is a widely used technology in local area networks (“LAN”) and other computer networks. The Institute for Electrical and Electronics Engineers (“IEEE”) has developed standards for Ethernet communication systems. See, for example, IEEE 802.3, incorporated herein by reference in its entirety. The IEEE 802.3 standards have been adopted by the International Organization for Standardization (“ISO”), making the IEEE 802.3 standards worldwide standards.
In an Ethernet network, a computer utilizes an Ethernet transceiver to transmit and receive signals between the computer and a network. The transceiver typically interfaces with the network via a physical link medium, such as copper or fiber.
An Ethernet transceiver typically includes a media access controller (“MAC”) that interfaces with applications running on the computer. Alternatively, an Ethernet module can include a switch or an optical module. An Ethernet transceiver also includes a physical layer device, or “PHY” that interfaces between the MAC/switch and a physical link media. PHYs typically interface with physical link media using serialized data streams. PHYs typically interface with MACs/switches using packet-based interfaces.
PHYs can be designed to interface with any of a variety of types of physical link medium (e.g., copper or fiber). PHYs can also be designed to interface with MAC/switches through any of a variety of interface format.
What is needed is a PHY that can selectively interface with MAC/switches in any of a plurality of modes, and that can selectively interface with any of a plurality of types of physical link media, depending upon the availability of active link partners.